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Re: 67 427 oiling questions
Keith,
I hope I remember this correctly. I think a grooved 65-66 cam can be used in a 67 block with a 67 style rear cam bearing but a non grooved 67 and later cam cannot be used in a 65-66 block.
This may explain why GM continued using up inventory of glooved cams in some 67's.
For racing, in the late 60's, GM recommended that the groove in a 65-66 cam be filled if it were to be used in a 67 and later block but I don't think there was enough of an oil leak at the bearing to be concerned about. In fact, in later years, GM no longer recommended filling the groove.Comment
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Re: 67 427 oiling questions
they recommended that you reduce the size of the oil feed hole in the bearing to 1/16" diameter by soldering the original hole shut and drilling a new one 1/16" dia. i did that when i did used GM grooved cams in later blocks. on street engine you did not need to do this because the internal oil leak was not a problem .Comment
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Re: 67 427 oiling questions
Keith-----
I expect this was a situation in which the 3904364 core was machined into the earlier configuration. The only thing that would have been needed to be done was the machining of the rear cam journal for the 65-66 groove. Usually, whenever a camshaft is not identified by the markings between the lobes, the end of the journal was stamped with the actual part number of the finished camshaft. Why this camshaft was used in the 1967 engine is something I do not know.
By the way, to minimize machining costs, the core for the earlier camshaft had the rear journal groove formed as part of the casting and only finish machining was then required.In Appreciation of John HinckleyComment
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Re: 67 427 oiling questions
clem------
I only recollect seeing the number stamped on the ends of camshafts that were made from generic cores. In those cases, the numbers between the lobes would not identify the camshaft. Of course, I would expect this would also be done in a case like Keith's in which the finished camshaft was not identified by the numbers between the lobes because the core used was designed for another finished camshaft and was "converted" by machining.
However, as you say, it's very possible that all original cams had the end stamping. I just do not recollect it. There are lots of things I don't recollect.In Appreciation of John HinckleyComment
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Re: 67 427 oiling questions
Wayne------
The seller has his applications WAY OFF. The GM #3994094 camshaft was NEVER used for any PRODUCTION application and, as far as I can tell, it was never used as part of any SERVICE engine assembly. It was a SERVICE-only camshaft designed for racing applications. Personally, I consider it way too radical for street operation. But, I have a penchant for civilized street engines and some other folks don't.
The GM #3994094 camshaft was discontinued without supercession in December, 1987.In Appreciation of John HinckleyComment
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Re: 67 427 oiling questions
Having been through this long before the internet or the desk top PC, Wayne got it, that is the service cams cannot be used in the 65 66 blocks. I do recall that the rebuilders charged a good extra to machine that.
Keith, Are you sure the cam is the original - never has someone been in the engine?Comment
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Re: 67 427 oiling questions
i know the engine was apart before. the dates on the cam barrings are a 67 date where as the crank barrings are dated 1973. but what really was done I have no clueComment
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Re: 67 427 oiling questions
The mystery is solved. Got a packet of receipts from the seller today and there was a bill from 1974 for a total engine rebuild with that cam part number on the bill. Also the owner went though five starters on this carComment
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